Can I send newsletters?

You can send newsletters (if they are real newsletters and not spam) from our servers, but you can send only up to 100 messages per hour (using webmail), 19 messages/minute (using PHP) and 9 mails/minute (using SMTP). If You exceed any of these limits, the account is going to be suspended.
If you need to send more messages, you need to "split" them accordingly.